Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for River Falls should be reffered to in order to estimate when it's a good idea to plant cardinal flower.

Planting Calendar for Cardinal Flower

Frost tolerance for cardinal flower:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

It's a bad idea to plant cardinal flower until after all chance of frost has passed because they require warm weather.

The earliest that you can plant cardinal flower in River Falls is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant cardinal flower and expect a good harvest is probably August. You probably don't want to wait any later than that or else your cardinal flower may not have a chance to fully mature. You can get started a few weeks earlier by starting your cardinal flower indoors.

Last Frost Date

In River Falls the average date of last frost happens on May 15. In the coldest months of winter you should expect an average low temperature of -25°F.

Always keep in mind that USDA zone info for River Falls may not be accurate from year to year and the actual date of last frost changes from year to year. Since half of the time in River Falls it frosts late in the year after May 15 be ready to cover your cardinal flower in the event of one of those late frosts.

USDA Zone Info for River Falls

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in River Falls

You may be interested in your other planting guides for River Falls.